UV-curable organopolysiloxane composition and its use

Abstract

An object of the present invention is to provide a UV-curable organopolysiloxane composition without using an organic solvent, and the cured product obtained by curing has sufficient hardness and toughness with particularly excellent workability when applied to a substrate. The solution comprises (A1) a branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of 2,500 or more, (A2) a branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of less than 2,500, (A3) a linear organopolysiloxane having two or more alkenyl groups in the molecule, (B) an organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule and having an amount within a range where the molar ratio of the silicon-bonded hydrogen atoms in component (B) to the alkenyl groups in component (A) is 0.5 to 4.0, and (C) a photoactivated hydrosilylation catalyst, and the mass ratio of components (A1), (A2), and (A3) satisfies the following formula (1): [(A1)+(A2)] / (A3)>1.3 (1), the content X of alkenyl groups per 100 g of the whole composition satisfies the following formula (2): 110≦X≦220 (2), a UV-curable organopolysiloxane composition, wherein the viscosity measured at 25 °C using an E-type viscometer for the whole composition is in the range of more than 80 mPas to 500 mPas or less, and substantially no organic solvent is contained in the composition.

Description

Technical Field

[0001] The present invention relates to an ultraviolet (UV) curable organopolysiloxane composition containing an organosiloxane and / or organopolysiloxane that can be cured by actinic rays such as ultraviolet rays or electron beams. In particular, the present invention relates to a UV curable organopolysiloxane composition in which the resulting cured product has excellent coating ability, high hardness, and good toughness. The curable organopolysiloxane composition of the present invention has a low viscosity of less than 500 mPas and is suitable as an insulating material for electronic and electrical devices, particularly as a material for use as a coating agent. Furthermore, since this composition substantially does not contain an organic solvent, it contributes to the simplification of the process. In addition, the cured product obtained by curing the composition has good releasability and is useful as a material (also referred to as a mask, master, template, or mold material) for a stamp applied to nanoimprint lithography.

Background Art

[0002] Silicone resins are used as coating agents, potting agents, insulating materials, etc. for electronic and electrical devices because of their high heat resistance and excellent chemical stability. Among silicone resins, UV curable silicone compositions have also been reported.

[0003] As a process for forming a fine pattern of a semiconductor device, a photolithography process is known. Also, silicone materials therefor are generally known. For example, Japanese Patent Application Laid-Open No. 2009-298887 discloses a photo-patternable material comprising a polysiloxane obtained by hydrolysis and condensation reaction, a photoacid generator, and an organic solvent.

[0004] On the other hand, as an alternative technology to the photolithography process, nanoimprint lithography has been proposed and is expected to contribute to a significant reduction in the manufacturing cost of semiconductors. This technology consists of a process of bringing a stamp made of a UV-transmissive material such as quartz and having a fine pattern into contact with a curable material such as an acrylate-based resin, a process of curing the curable material, and subsequently a process of releasing the stamp from the cured body. The stamp deteriorates due to repeated use and needs to be replaced periodically. However, stamps made of quartz are expensive, and stamps made of resin materials are being studied.

[0005] Japanese Patent Application Laid-Open No. 2015-214637 discloses a nanoimprint master article comprising a laminate body obtained by adhesion between a cured body from a UV-curable organopolysiloxane resin composition containing a linear organopolysiloxane having at least two alkenyl groups, a three-dimensional resinous organopolysiloxane having a specific amount of alkenyl groups, an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule and not containing an alkoxy group, and a photoactivatable hydrosilylation catalyst, and a thermoplastic resin substrate. However, since this composition has a high content of the linear organopolysiloxane having at least two alkenyl groups, it forms an elastomeric cured body having a low hardness. Further, the viscosity of the composition is higher than 2700 mPas and is not suitable for coating process applications such as spin coating applications.

[0006] Furthermore, Japanese Patent Application Laid-Open No. 2010-47646 discloses a branched organopolysiloxane having at least three alkenyl groups, a linear organopolysiloxane having at least two alkenyl groups, SiO 4 / 2 units and R 3 SiO 1 / 2An organohydrogenpolysiloxane composed of units and having at least 3 silicon-bonded hydrogen atoms in the molecule, and a UV-curable organopolysiloxane resin composition containing a (methylcyclopentadienyl)trialkylplatinum complex are disclosed. Since the cured product from this composition has a high content of branched organopolysiloxane, its hardness is sufficiently high. However, because the viscosity of the composition is as high as 5,100 mPas, it is not suitable for coating process applications such as spin coating.

[0007] On the other hand, Japanese Patent Application Laid-Open No. 2005-227701 discloses a curable organopolysiloxane resin composition applied to an optical transmission article containing an organopolysiloxane having at least 2 silicon-bonded alkenyl groups in the molecule, an organopolysiloxane or an organosilicon compound having at least 2 silicon-bonded hydrogen atoms in the molecule, and a hydrosilylation reaction catalyst. This composition has a low viscosity of 800 mPas or less, and the flexibility of its cured product is good. However, no research has been done on the relationship between the mechanical strength and the molecular weight of the cured product of branched organopolysiloxane. In addition, the cured product from this composition does not have a sufficiently high hardness. Furthermore, this patent document does not mention UV curability at all.

Prior Art Documents

Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-214637 Patent Document 2: Japanese Patent Application Laid-Open No. 2010-047646 Patent Document 3: Japanese Patent Application Laid-Open No. 2005-227701

Summary of the Invention

[0009] Problems to be Solved by the Invention As described above, curable organopolysiloxane compositions and low-viscosity organopolysiloxane compositions applied to nanoimprint stamp articles are known. However, there is still a need for a UV-curable organopolysiloxane composition in which the cured product obtained therefrom has sufficient hardness and toughness, excellent workability for application to a substrate, and particularly a low viscosity. That is, an object of the present invention is to provide a UV-curable organopolysiloxane composition, and the cured product obtained by curing has sufficient hardness and toughness together with particularly excellent workability when applied to a substrate.

[0010] Means for Solving the Problems The present invention is completed by using (A) a mixture of at least two or more types of a branched organopolysiloxane having at least two alkenyl groups in the molecule and a linear organopolysiloxane having at least two alkenyl groups in the molecule with different molecular weights, (B) an organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule, and a photoactivated hydrosilylation catalyst, so that the composition does not contain an organic solvent as a whole, and using an E-type viscometer, the viscosity measured at 25°C is in the range of more than 80 mPas to 500 mPas or less. By controlling the content of alkenyl groups in the composition design of the UV-curable organopolysiloxane composition and the composition, it is found that the curable composition is excellent in workability such as coating ability, and the hardness and toughness of the cured body obtained therefrom are sufficiently high.

[0011] The ultraviolet (UV)-curable organopolysiloxane composition of the present invention is (A1) a branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of 2,500 or more, and (A2) a branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of less than 2,500, and (A3) a linear organopolysiloxane having two or more alkenyl groups in the molecule, and (B) An organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule, wherein the molar ratio of the silicon-bonded hydrogen atoms in component (B) to the alkenyl groups in component (A) is in the range of 0.5 to 4.0, and an organopolysiloxane, (C) A photoactivated hydrosilylation catalyst, and, The mass ratio of components (A1), (A2), and (A3) satisfies the following formula (1), [(A1)+(A2)] / (A3)>1.3 (1) The content X of alkenyl groups per 100 g of the whole composition satisfies the following formula (2): 110≦X≦220 (2), For the whole composition, the viscosity measured at 25 °C using an E-type viscometer is in the range of more than 80 mPas to 500 mPas or less, Characterized in that the organic solvent is substantially not contained in the composition.

[0012] When the total mass of components (A) to (C) in the composition is 100 parts by mass, the parts by mass of components (A1), (A2), and (A3) are preferably as follows: (A1): 25 to 75 parts by mass, (A2): 3 to 60 parts by mass, and (A3): 5 to 40 parts by mass.

[0013] Component (A3) is preferably a linear organopolysiloxane having an alkenyl group at its molecular terminal.

[0014] Component (B) is preferably a linear organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule.

[0015] Component (A1) has an alkenyl group and has the following average unit formula: (R 1 3SiO 1 / 2 ) a1 (R 1 2SiO 2 / 2 ) b1 (R 1 SiO 3 / 2 ) c1 (SiO 4 / 2 ) d1 (3) (wherein R 1 is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, at least two of all R 1 are alkenyl groups having 2 to 12 carbon atoms, and a1, b1, c1, and d1 are numbers satisfying the following conditions: a1 + b1 + c1 + d1 = 1, 0 ≦ a1 ≦ 0.5, 0 ≦ b1 ≦ 0.4, 0 ≦ c1 ≦ 0.8, and 0 ≦ d1 ≦ 0.7, 0.5 ≦ c1 + d1 ≦ 0.8) is preferably a branched organopolysiloxane represented by

[0016] Component (A2) has an alkenyl group and has the following average unit formula: (R 2 3SiO 1 / 2 ) a2 (R 2 2SiO 2 / 2 ) b2 (R 2 SiO 3 / 2 ) c2 (SiO 4 / 2 ) d2 (4) (wherein R 2 is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, at least two of all R 2 are alkenyl groups having 2 to 12 carbon atoms, and a2, b2, c2, and d2 are numbers satisfying the following conditions: a2 + b2 + c2 + d2 = 1, 0 ≦ a2 ≦ 0.5, 0 ≦ b2 ≦ 0.8, 0 ≦ c2 < 0.5, and 0 ≦ d2 < 0.5, 0 < c2 + d2 < 0.5) is preferably a branched organopolysiloxane represented by

[0017] It is preferable that the mass ratio of components (A1), (A2), and (A3) satisfies the following formula: [(A1) + (A2)] / (A3) ≧ 1.5 (5).

[0018] Regarding the cured body obtained by curing the composition, the hardness measured at 25 °C using a type D durometer is preferably 30 or more.

[0019] For the entire composition, the viscosity measured at 25 °C using an E-type viscometer is preferably in the range of 100 to 350 mPas.

[0020] Component (C) is preferably an unsubstituted or alkyl-substituted (cyclopentadienyl)trialkylplatinum complex.

[0021] The UV-curable organopolysiloxane composition of the present invention is suitable for use as an insulating coating agent. Therefore, the present invention provides an insulating coating agent containing the UV-curable organopolysiloxane composition.

[0022] The present invention also provides a cured product obtained by curing the UV-curable organopolysiloxane composition.

[0023] Furthermore, the present invention provides the use of the UV-curable organopolysiloxane composition as a stamp-forming material applied to nanoimprint lithography.

[0024] Advantages of the Invention The UV-curable organopolysiloxane composition of the present invention has a low viscosity without using an organic solvent, is excellent in its coating ability onto a substrate through a spin coating process or the like, has good curability, and the hardness of the cured product obtained by curing is sufficiently high and has good toughness.

Embodiments for Carrying Out the Invention

[0025] First, the UV-curable organopolysiloxane composition of the present invention (hereinafter, may be referred to as "curable composition" or "UV-curable composition") will be further described in detail below. Further, in the present invention, the molecular weight means the weight average molecular weight which is a relative value with respect to standard polystyrene measured by gel permeation chromatography (GPC) method.

[0026] The curable composition of the present invention is (A1) a branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of 2,500 or more, (A2) a branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of less than 2,500, (A3) a linear organopolysiloxane having two or more alkenyl groups in the molecule, (B) an organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule, and having an amount of silicon-bonded hydrogen atoms in component (B) relative to the alkenyl groups in component (A) within the range of 0.5 to 4.0, (C) a photoactivated hydrosilylation catalyst, and the mass ratio of components (A1), (A2), and (A3) satisfies the following formula (1), [(A1)+(A2)] / (A3)>1.3 (1) the content X of alkenyl groups per 100 g of the whole composition satisfies the following formula (2): 110≦X≦220 (2), for the whole composition, the viscosity measured at 25 °C using an E-type viscometer is in the range of more than 80 mPas to 500 mPas or less, and is characterized in that an organic solvent is substantially not contained in the composition.

[0027] When this UV curable composition contains component (C) of the photoactivated hydrosilylation catalyst, upon irradiation with active light, for example, UV light, the catalyst is activated in the form of a hydrosilylation reaction catalyst, and cures by crosslinking caused by an addition reaction between the alkenyl groups in component (A) and the silicon-bonded hydrogen atoms (Si-H), that is, hydrosilyl groups, in component (B).

[0028] Components (A), (B), (C), and other optional components will be further described in detail as follows.

[0029] [Component (A)] Component (A) is the main component of this composition and is a mixture of organopolysiloxanes having alkenyl groups. Specifically, component (A) consists of the following components (A1), (A2), and (A3), and the mass ratios of the respective components satisfy a specific relationship.

[0030] [Component (A1): A branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of 2,500 or more] Component (A1) is an organopolysiloxane having an alkenyl group, that is, a curable group containing a carbon-carbon double bond. The carbon-carbon double bond can react with an Si-H group by a hydrosilylation reaction and is not limited to alkenyl groups having a specific chemical structure. The alkenyl group is preferably an alkenyl group at the molecular end, and examples include alkenyl groups having C2-C20 such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, and 4-vinylphenyl group, but are not limited thereto. The alkenyl group is particularly preferably selected from vinyl group, allyl group, and hexenyl group, and most preferably vinyl group.

[0031] The branched organopolysiloxane of component (A1) is branched, and more specifically has a branched-chain structure or a resinous (network) structure, has two or more of the alkenyl groups in the molecule, and has a molecular weight of 2,500 or more, preferably 3,000 or more. By blending this branched organopolysiloxane having a high molecular weight, the hardness and toughness of the cured body obtained by curing the composition are improved. Component (A1) preferably contains 25 or more, more preferably 30 or more silicon atoms. As component (A1), a combination of one type or at least two types of branched organopolysiloxanes can be used.

[0032] In addition to the alkenyl group, the branched organopolysiloxane of component (A1) may contain any functional group selected from the group consisting of a monovalent hydrocarbon group, a hydroxyl group, and an alkoxy group that does not contain a carbon-carbon double bond in the molecule. Examples of the monovalent hydrocarbon group include an unsubstituted monovalent hydrocarbon group and a fluorine-substituted monovalent hydrocarbon group. The unsubstituted or fluorine-substituted monovalent hydrocarbon group is preferably a group selected from an unsubstituted or fluorine-substituted alkyl group, a cycloalkyl group, an arylalkyl group, and an aryl group having 1 to 20 carbon atoms. Examples of the above alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, a pentyl group, an octyl group, and other groups, and a methyl group is particularly preferred. Examples of the above cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and the like. Examples of the above arylalkyl group include a benzyl group, a phenylethyl group, and the like. Examples of the above aryl group include a phenyl group, a naphthyl group, and the like. Examples of the fluorine-substituted monovalent hydrocarbon group include a 3,3,3-trifluoropropyl group and a 3,3,4,4,5,5,5,6,6,6-nonafluorohexyl group. The fluorine-substituted monovalent hydrocarbon group is preferably a 3,3,3-trifluoropropyl group.

[0033] In the branched organopolysiloxane of component (A1), the Si atom-bonded organic group other than the alkenyl group is preferably essentially a methyl group. That is, among all the Si atom-bonded organic groups other than the alkenyl group, preferably 95 mol% or more, more preferably 99 mol% or more, and most preferably 100 mol% of the organic groups are methyl groups. Therefore, the most preferred embodiment of component (A1) is an organosiloxane having a vinyl group as the alkenyl group and the Si atom-bonded organic group other than the alkenyl group being essentially a methyl group, preferably one type or at least a combination of two types selected from the group consisting of a branched-chain organopolysiloxane and a resinous organopolysiloxane.

[0034] The branched organopolysiloxane of component (A1) is usually in a solid state, but the state can vary depending on its molecular weight, its molecular weight distribution, and the type of substituent on the Si atom. When preparing the UV curable organopolysiloxane composition of the present invention, component (A1) can be directly blended as one of the raw materials. On the other hand, in order to simplify the manufacturing process, it is preferable that component (A1) be blended as a liquid mixture by premixing component (A1) with another organopolysiloxane, specifically a linear organopolysiloxane (A3) having an alkenyl group.

[0035] Preferably, component (A1) is a branched organopolysiloxane or a mixture of two or more types represented by the following average unit formula: (R 1 3SiO 1 / 2 ) a1 (R 1 2SiO 2 / 2 ) b1 (R 1 SiO 3 / 2 ) c1 (SiO 4 / 2 ) d1 (3) In the formula, R 1 is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, and at least 2 of all R 1 are alkenyl groups having 2 to 12 carbon atoms, and a1, b1, c1, and d1 are numbers satisfying the following conditions: a1 + b1 + c1 + d1 = 1, 0 ≦ a1 ≦ 0.5, 0 ≦ b1 ≦ 0.4, 0 ≦ c1 ≦ 0.8, 0 ≦ d1 ≦ 0.7, 0.5 ≦ c1 + d1 ≦ 0.8. R 1When representing an alkenyl group and other monovalent hydrocarbon groups having 1 to 12 carbon atoms, the aforementioned groups can be used. Regarding the preferred ratio of each siloxane unit, when a1, b1, c1, and d1 are within the said range, the high molecular weight of the branched organopolysiloxane can be easily designed. Further, when c1 + d1 is greater than the said lower limit, it is preferable because the molecular weight of the branched organopolysiloxane tends to be larger. On the other hand, when c1 + d1 is lower than the said upper limit, it is preferable because more stable production of the branched organopolysiloxane becomes possible.

[0036] Examples of the branched organopolysiloxane having an alkenyl group that can be used as the component (A1) include organopolysiloxanes represented by the following average unit formula. In the following formula, each of Me, Vi, and Ph represents a methyl group, a vinyl group, and a phenyl group, respectively, and n, m, l, and k each represent the molar ratio of each siloxane unit, each being greater than 0 and less than 1, provided that these values satisfy the condition of n + m + l + k = 1. (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (SiO 4 / 2 ) l [0.5≦l] (Me2ViSiO 1 / 2 ) n (SiO 4 / 2 ) m [0.5≦m] (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (Me2SiO 2 / 2 ) l (SiO 4 / 2 ) k [0.5≦k] (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (SiO 4 / 2 ) l [0.5≦l] (Me3SiO1 / 2 ) n (MeViSiO 2 / 2 ) m (SiO 4 / 2 ) l [0.5 ≦ l] (Me2ViSiO 1 / 2 ) n (MeSiO 3 / 2 ) m [0.5 ≦ m] (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (MeSiO 3 / 2 ) l [0.5 ≦ l] (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (Me2SiO 2 / 2 ) l (MeSiO 3 / 2 ) k [0.5 ≦ k] (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (MeSiO 3 / 2 ) l [0.5 ≦ l] (Me2ViSiO 1 / 2 ) n (PhSiO 3 / 2 ) m [0.5 ≦ m] (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (PhSiO 3 / 2 ) l [0.5 ≦ l] (Me2ViSiO 1 / 2 ) n (MePhSiO 2 / 2 ) m (PhSiO 3 / 2 ) l [0.5 ≦ l] (Me2ViSiO 1 / 2 ) n (Ph2SiO 2 / 2 )m (PhSiO 3 / 2 ) l [0.5≦l]

[0037] The organopolysiloxane of component (A1) can contain a small amount of silanol groups or alkoxysilyl groups that do not affect its hydrosilylation reaction. In this specification, a small amount means less than 5 mol% of all substituents bonded to Si atoms.

[0038] [Component (A2): Branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of less than 2,500] The organopolysiloxane of component (A2) is, like component (A1), an organopolysiloxane having an alkenyl group, that is, a curable group containing a carbon-carbon double bond. The carbon-carbon double bond can react with the Si-H group by a hydrosilylation reaction and is not limited to alkenyl groups having a specific chemical structure. The alkenyl group is particularly preferably selected from vinyl group, allyl group, and hexenyl group, and the vinyl group is most preferred.

[0039] The branched organopolysiloxane of component (A2) is branched, more specifically, has a branched-chain structure or a resinous (network) structure, has two or more of said alkenyl groups in the molecule, and is an organopolysiloxane having a molecular weight of less than 2,500, preferably less than 2,000, and is usually liquid. By blending this liquid branched organopolysiloxane having a lower molecular weight, the viscosity of the whole composition is reduced and its coating ability is improved. Furthermore, by using component (A2) in combination, it contributes to increasing the hardness of the cured body obtained by curing the composition. The component (A2) preferably contains less than 25, more preferably less than 20 silicon atoms. As component (A2), a combination of one kind or at least two kinds of branched organopolysiloxanes can be used.

[0040] In addition to the alkenyl group, the branched organopolysiloxane of component (A2) can contain any functional group selected from the group consisting of monovalent hydrocarbon groups, hydroxyl groups, and alkoxy groups that do not contain a carbon-carbon double bond in the molecule. In the present specification, the same groups exemplified for component (A1) can be used as these functional groups.

[0041] In the branched organopolysiloxane of component (A2), the Si atom-bonded organic groups other than the alkenyl group are preferably essentially methyl groups. That is, among all the Si atom-bonded organic groups other than the alkenyl group, preferably 95 mol% or more, more preferably 99 mol% or more, and most preferably 100 mol% of the organic groups are methyl groups. Therefore, the most preferred embodiment as component (A2) is an organosiloxane having a vinyl group as the alkenyl group and the Si atom-bonded organic groups other than the alkenyl group being essentially methyl groups, and preferably, it is one type or a combination of at least two types selected from the group of branched-chain organopolysiloxanes and resinous organopolysiloxanes.

[0042] Preferably, component (A2) is a branched organopolysiloxane represented by the following average unit formula or a mixture of two or more types: (R 2 3SiO 1 / 2 ) a2 (R 2 2SiO 2 / 2 ) b2 (R 2 SiO 3 / 2 ) c2 (SiO 4 / 2 ) d2 (4) In the formula, R 2 is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, and all R 2At least two of them are alkenyl groups having 2 to 12 carbon atoms, and a2, b2, c2, and d2 are the following conditions: a2 + b2 + c2 + d2 = 1, 0 ≦ a2 ≦ 0.5, 0 ≦ b2 ≦ 0.8, 0 ≦ c2 < 0.5, and 0 ≦ d2 < 0.5, 0 < c2 + d2 < 0.5 are numbers that satisfy. R 2 When R represents an alkenyl group and another monovalent hydrocarbon group having 1 to 12 carbon atoms, for the group R 1 The aforementioned groups can be used. Regarding the preferred ratio of each siloxane unit, when a2, b2, c2, and d2 are within the said range, the lower molecular weight of the branched organopolysiloxane can be easily designed. Furthermore, when c2 + d2 is within the said range, it is preferable to form a branched organopolysiloxane, and there is a tendency that the molecular weight does not become too high.

[0043] Examples of the branched organopolysiloxane having an alkenyl group that can be used as the component (A2) include organopolysiloxanes represented by the following average unit formula. In the following formula, each of Me, Vi, and Ph represents a methyl group, a vinyl group, and a phenyl group, and n, m, l, and k each represent the molar ratio of each siloxane unit, and each is greater than 0 and less than 1, provided that these values satisfy the condition of n + m + l + k = 1. (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (SiO 4 / 2 ) l [l < 0.5] (Me2ViSiO 1 / 2 ) n (SiO 4 / 2 ) m [m < 0.5, preferably an organopolysiloxane that satisfies 3.0 ≦ n / m ≦ 4.0 (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (Me2SiO 2 / 2 ) l (SiO 4 / 2 ) k [k < 0.5] (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (SiO 4 / 2 ) l [l < 0.5] (Me3SiO 1 / 2 ) n (MeViSiO 2 / 2 ) m (SiO 4 / 2 ) l [l < 0.5] (Me2ViSiO 1 / 2 ) n (MeSiO 3 / 2 ) m [m < 0.5, preferably an organopolysiloxane satisfying 1.5 ≤ n / m ≤ 3.0 (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (MeSiO 3 / 2 ) l [l < 0.5] (Me3SiO 1 / 2 ) n (Me2ViSiO 1 / 2 ) m (Me2SiO 2 / 2 ) l (MeSiO 3 / 2 ) k [k < 0.5] (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (MeSiO 3 / 2 ) l [l < 0.5] (Me2ViSiO 1 / 2 ) n (PhSiO 3 / 2 ) m [m < 0.5, preferably an organopolysiloxane satisfying 1.5 ≤ n / m ≤ 3.0 (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (PhSiO 3 / 2 ) l[l < 0.5] (Me2ViSiO 1 / 2 ) n (MePhSiO 2 / 2 ) m (PhSiO 3 / 2 ) l [l < 0.5] (Me2ViSiO 1 / 2 ) n (Ph2SiO 2 / 2 ) m (PhSiO 3 / 2 ) l [l < 0.5]

[0044] The organopolysiloxane of component (A2) can contain a small amount of silanol groups or alkoxysilyl groups that do not affect its hydrosilylation reaction. In this specification, a small amount means less than 5 mol% of all substituents bonded to Si atoms.

[0045] [Component (A3): Linear organopolysiloxane having two or more alkenyl groups in the molecule] Component (A3), like component (A1) and component (A2), is a linear organopolysiloxane having an alkenyl group, that is, a curable group containing a carbon-carbon double bond. The carbon-carbon double bond can react with the Si-H group by a hydrosilylation reaction and is not limited to alkenyl groups having a specific chemical structure. Alkenyl groups particularly preferably selected from vinyl groups, allyl groups, and hexenyl groups, and a vinyl group is most preferred.

[0046] Component (A3) is a linear organopolysiloxane having an average of 2 or more of such alkenyl groups in the molecule. From the viewpoint of providing flexibility and toughness to the cured product from the curable composition, component (A3) is preferably a linear organopolysiloxane having alkenyl groups at both ends. The degree of polymerization of component (A3), that is, the number of silicon atoms contained, is not limited, but component (A3) can contain an average of 5 or more, more preferably 10 or more silicon atoms per molecule, and further, an average of 1000 or less, more preferably 500 or less silicon atoms per molecule. In particular, from the viewpoint of controlling the viscosity of the curable composition, component (A3) preferably contains 30 to 200 silicon atoms. By blending this component (A3), in the cured product obtained by curing the composition, the viscosity of the whole composition is decreased, and its flexibility and toughness are improved. As such a linear organopolysiloxane having an alkenyl group, one kind or a combination of at least two kinds can be used.

[0047] In addition to the alkenyl group, the linear organopolysiloxane of component (A3) can contain any functional group selected from the group consisting of a monovalent hydrocarbon group not containing a carbon-carbon double bond, a hydroxyl group, and an alkoxy group in the molecule. In the present specification, the same groups exemplified for components (A1) and (A2) can be used as these functional groups.

[0048] In the linear organopolysiloxane of component (A3), similar to component (A1) or component (A2), the Si atom-bonded organic group other than the alkenyl group is preferably essentially a methyl group. That is, among all the silicon atom-bonded organic groups other than the alkenyl group, preferably 95 mol% or more, more preferably 99 mol% or more, and most preferably 100 mol% of the organic groups are methyl groups. Therefore, the most preferred embodiment as component (A3) is a linear organosiloxane having a vinyl group as the alkenyl group and the silicon atom-bonded organic group other than the alkenyl group being essentially a methyl group, preferably one kind or a combination of at least two kinds of linear organopolysiloxanes having vinyl groups at both ends.

[0049] Examples of the linear organopolysiloxane having an alkenyl group that can be used as the component (A3) include organopolysiloxanes represented by the following average unit formulas. In the following formulas, each of Me, Vi, and Ph represents a methyl group, a vinyl group, and a phenyl group, respectively, and n, m, and l each represent the molar ratio of each siloxane unit, each being greater than 0 and less than 1, provided that these values satisfy the condition of n + m + l = 1. (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (MeViSiO 2 / 2 ) l (Me3SiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (MeViSiO 2 / 2 ) l (Me3SiO 1 / 2 ) n (MeViSiO 2 / 2 ) m (Me2ViSiO 1 / 2 )n (MePhSiO 2 / 2 ) m (Me2ViSiO 1 / 2 ) n (Me2SiO 2 / 2 ) m (Ph2SiO 2 / 2 ) l (Me2ViSiO 1 / 2 ) n (Ph2SiO 2 / 2 ) m (Me3SiO 1 / 2 ) n (MePhSiO 2 / 2 ) m (MeViSiO 2 / 2 ) l (Me3SiO 1 / 2 ) n (Ph2SiO 2 / 2 ) m (MeViSiO 2 / 2 ) l

[0050] When the total mass of components (A) to (C) in the composition is 100 parts by mass, the parts by mass of components (A1), (A2), and (A3) are preferably as follows: (A1): 25 to 75 parts by mass, (A2): 3 to 60 parts by mass, and (A3): 5 to 40 parts by mass, and it is preferable that they satisfy these. These mass ratios of components (A1), (A2), and (A3) can be determined in consideration of the viscosity of the composition, the hardness and toughness of the cured body obtained by curing the composition.

[0051] In the curable composition of the present invention, the mass ratio of components (A1), (A2), and (A3) needs to satisfy the following formula (1): [(A1)+(A2)] / (A3)>1.3 (1) This formula (1) means that the mass ratio of the branched organopolysiloxanes (A1, A2) to the linear organopolysiloxane exceeds 1.3. From the viewpoint of hardness, particularly the hardness of the cured product suitable as a stamp material applied to nanoimprint lithography, the preferred value of the mass ratio is 1.5 or more. A value in the range of 1.5 to 10.0 is more preferred. On the other hand, when the value is 1.3 or less, since the proportion of the linear organopolysiloxane in the composition is higher, the hardness of the cured product becomes lower, and the object of the present invention cannot be achieved.

[0052] Furthermore, the content (X, unit: mmol) of alkenyl groups per 100 g of the entire organopolysiloxane composition needs to satisfy the following formula (2): 110 ≦ X ≦ 220 (2) When this value is lower than 110, it becomes difficult to design a composition having a viscosity preferable for application to the coating process, or the cured product after curing tends to have a lower hardness. On the other hand, when the value exceeds 220, the toughness of the cured product after curing becomes worse, and the object of the present invention cannot be achieved. The range of the X value is preferably 130 ≦ X ≦ 200, and more preferably 130 ≦ X ≦ 180.

[0053] [Component (B): Organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule] The organopolysiloxane having silicon-bonded hydrogen atoms of component (B) (hereinafter, may be referred to as "organohydrogenpolysiloxane") has an average of two or more silicon-bonded hydrogen atoms in the molecule and can act as a crosslinking agent through its hydrosilylation reaction with component (A) having an alkenyl group to form a crosslinked structure.

[0054] One type or two or more types selected from the group consisting of organohydrogenpolysiloxanes having a linear form, a branched-chain form, a cyclic form, and a resinous form can be used as component (B). Such organohydrogenpolysiloxanes are compounds well-known in the technical field of the present invention.

[0055] In the case of component (B), the linear organohydrogenpolysiloxane is exemplified by 1,1,3,3 - tetramethyldisiloxane, methylhydrogenpolysiloxane blocked at both ends of the molecular chain with trimethylsiloxy groups, dimethylsiloxane / methylhydrogensiloxane copolymer blocked at both ends of the molecular chain with trimethylsiloxy groups, dimethylpolysiloxane blocked at both ends of the molecular chain with dimethylhydrogensiloxy groups, dimethylsiloxane / methylhydrogensiloxane copolymer blocked at both ends of the molecular chain with dimethylhydrogensiloxy groups, methylhydrogensiloxane / diphenylsiloxane copolymer blocked at both ends of the molecular chain with trimethylsiloxy groups, and methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymer blocked at both ends of the molecular chain with trimethylsiloxy groups, but is not limited thereto. One kind or a combination of at least two kinds of these linear organohydrogenpolysiloxanes can be used. As component (B) of the present invention, among the silicon - atom - bonded organic groups other than the silicon - atom - bonded hydrogen atoms in the organohydrogenpolysiloxane, preferably 80 mol% or more, more preferably 90 - 100 mol% of the organic groups are methyl groups.

[0056] Examples of component (B) include branched, cyclic, and resinous organohydrogenpolysiloxanes as 1,3,5,7 - tetramethylcyclotetrasiloxane, tris(dimethylhydrogensiloxy)methylsilane, tris(dimethylhydrogensiloxy)phenylsilane, tetrakis(dimethylhydrogensiloxy)silane, hydrolysis - condensation products of trimethoxysilane, and mixtures of two or more kinds selected therefrom. Further examples of resinous organohydrogenpolysiloxanes include M H MQ type, M H Q type, M H MT type, M H T type, M H MQT type, M H QT type, M HMDQ type, M H MDD H Q type, M H DQ type, M H DD H Q type, M H MDT type, M H MDD H T type, M H DT type, M H DD H T type, M H MDQT type, M H MDD H QT type, M H DQT type, and M H DD H At least one of the organohydrogenpolysiloxane resins selected from the QT type is included, and the organohydrogenpolysiloxane contains SiO 4 / 2 units (Q units) and R 3 SiO 3 / 2 units (T units), R 3 3SiO 1 / 2 units (M units), R 3 3HSiO 1 / 2 units (M H units) and contains at least one branched siloxane unit selected therefrom. Optionally, R 3 2SiO 2 / 2 units (D units), R 3 HSiO 2 / 2 units (D H units). One type or a combination of two or more types thereof can be used. Further, the R 3 can independently be a methyl or phenyl group, preferably a methyl group.

[0057] The branched, cyclic, or resinous organohydrogenpolysiloxane of component (B) can contain a small amount of silanol groups or alkoxysilyl groups that do not affect its hydrosilylation reaction. In the present specification, a small amount means less than 5 mol% of all substituents bonded to Si atoms.

[0058] As the component (B), one kind or a combination of two or more kinds of the linear, branched, cyclic, and resinous organohydrogenpolysiloxanes can be used. Linear organohydrogenpolysiloxane is preferred.

[0059] As the component (B) of the present invention, the hydrogen content of the silicon atom-bonded hydrogen radical of the organohydrogenpolysiloxane is preferably within 0.1 to 1.6% by mass, more preferably within 0.2 to 1.5% by mass, and most preferably within 0.4 to 1.5% by mass.

[0060] The viscosity of the component (B) at 25°C is preferably 2 to 100 mPas. However, when combined with the component (A) and the component (C), an organohydrogenpolysiloxane having an optional viscosity in the range of more than 80 mPas to 500 mPas or less can be used for the whole composition, measured at 25°C using an E-type viscometer.

[0061] In the curable composition of the present invention, the content of the component (A) is such that the silicon-bonded hydrogen atoms in the component (B) are 0.5 to 4.0 moles, preferably 0.7 to 3.0 moles, and most preferably 0.7 to 2.0 moles, per 1 mole of the alkenyl group in the component (A). When the amount of the silicon-bonded hydrogen atoms in the component (B) is within the above range, a curable composition having good curability and excellent physical properties in the cured product after curing can be obtained.

[0062] [Component (C): Photoactivated hydrosilylation catalyst] The component (C) is a photoactivated hydrosilylation catalyst that provides curability by irradiating the curable composition of the present invention with actinic light (for example, UV light). To activate the component (C), UV (ultraviolet) irradiation with a wavelength of 280 to 380 nm is industrially easy to use. The exposure amount depends on the type of the high-energy ray-activated catalyst. In the case of ultraviolet light, the total exposure amount at a wavelength of 365 nm is preferably in the range of 100 mJ / cm 2 ~10 J / cm 2 .

[0063] Component (C) is not limited to a specific compound as long as it is a compound that exhibits catalytic activity as a hydrosilylation catalyst upon UV irradiation, but it is preferable to use a photoactivated platinum complex. Examples of the photoactivated platinum complex include (methylcyclopentadienyl)trimethylplatinum(IV), (cyclopentadienyl)trimethylplatinum(IV), (1,2,3,4,5-pentamethylcyclopentadienyl)trimethylplatinum(IV), (cyclopentadienyl)dimethylethylplatinum(IV), (cyclopentadienyl)dimethylacetylplatinum(IV), (trimethylsilylcyclopentadienyl)trimethylplatinum(IV), (methoxycarbonylcyclopentadienyl)trimethylplatinum(IV), (dimethylphenylsilylcyclopentadienyltrimethylcyclopentadienylplatinum(IV), trimethyl(acetylacetonato)platinum(IV), trimethyl(3,5-heptanedionato)platinum(IV), trimethyl(methylacetoacetate)platinum(IV), bis(2,4-pentanedionato)platinum(II), bis(2,4-hexanedionato)platinum(II), bis(2,4-heptanedionato)platinum(II), bis(3,5-heptanedionato)platinum(II), bis(1-phenyl-1,3-butanedionato)platinum(II), bis(1,3-diphenyl-1,3-propanedionato)platinum(II), and bis(hexafluoroacetylacetonato)platinum(II).

[0064] As component (C), a (cyclopentadienyl)trialkylplatinum complex or a derivative thereof obtained by substituting its cyclopentadienyl ligand with an alkyl group is preferable, and (methylcyclopentadienyl)trimethylplatinum(IV) is preferable from the viewpoints of versatility and availability. Also, as component (C), bis(2,4-pentanedionato)platinum(II) is preferable from the viewpoints of versatility and availability.

[0065] The amount of component (C) is an amount necessary to cure the curable composition of the present invention at an industrially sufficient curing rate. The amount of platinum metal atoms in component (C) is in the range of 1 to 500 ppm, preferably in the range of 5 to 100 ppm, more preferably in the range of 10 to 100 ppm, based on the mass of the UV-curable organopolysiloxane composition.

[0066] The curable composition of the present invention can optionally contain a hydrosilylation reaction inhibitor. Usually, a hydrosilylation reaction inhibitor is added to the composition to improve the pot life of the composition and obtain a stable curable composition. However, in order to avoid a decrease in the curing rate, the curable composition of the present invention should not contain a hydrosilylation reaction inhibitor. On the other hand, in order to extend the pot life of the curable composition, a hydrosilylation reaction inhibitor can be added to the composition. In this technical field, hydrosilylation reaction inhibitors are well-known, and examples thereof include alkynyl alcohols such as 1-ethynylcyclohexane-1-ol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyn-2-ol, enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne, methylalkenylsiloxane oligomers such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, alkyneoxysilanes such as dimethylbis(1,1-dimethyl-2-propynoxy)silane and methylvinylbis(1,1-dimethyl-2-propynoxy)silane, and triarylisocyanurate-based compounds.

[0067] In the UV curable organopolysiloxane composition of the present invention, when a hydrosilylation reaction inhibitor is used, the amount of the hydrosilylation reaction inhibitor is not particularly limited, but the hydrosilylation reaction inhibitor is preferably used in the range of 0.0001 to 1 part by mass, 0.01 to 1 part by mass, or 0.01 to 0.1 part by mass with respect to 100 parts by mass of the total amount of components (A) to (C).

[0068] [UV curable organopolysiloxane composition] The UV curable organopolysiloxane composition of the present invention contains the components (A), (B), and (C) as essential components, substantially does not contain an organic solvent, and the viscosity measured at 25 °C using an E-type viscometer for the whole composition is in the range of more than 80 mPas to 500 mPas or less. When the viscosity of the composition is within this range, the composition is excellent in its coating ability and can efficiently obtain a high-quality coating layer.

[0069] The viscosity of the whole composition is preferably in the range of 100 to 500 mPas, more preferably 100 to 350 mPas, and particularly preferably 200 to 350 mPas. In this embodiment, substantially not containing an organic solvent means that the content of the organic solvent is less than 0.05% by mass of the whole composition, and preferably the content is below the detection limit value using an analytical method such as gas chromatography. In the present invention, by controlling the molecular structure and molecular weight of components (A) and (B), the desired viscosity of the composition can be achieved.

[0070] In the curable composition of the present invention, according to the molecular lengths of components (A) and (B), the number of alkenyl groups or silicon atom-bonded hydrogen groups per molecule, the bonding positions of these reactive functional groups in the molecule, its molecular structure, the desired physical properties of the cured product therefrom, and its curing rate can be achieved, and the viscosity of the curable composition can be designed to have its desired value. Furthermore, the cured product obtained by curing the curable composition of the present invention is also included in the scope of the present invention.

[0071] The hardness of the cured product of the present invention is preferably such that its hardness measured by a Type D durometer at 25°C is 30 or more. A cured product having such hardness can be applied as a cured optical article such as a stamp material having good releasability with respect to an article having a pattern by nanoimprint lithography, and thus contributes to the improvement of productivity in the nanoimprint lithography process. On the other hand, if the hardness of the cured product is too high, its brittleness increases, which may cause lower productivity, so this is not preferable. The preferable Type D durometer hardness in the cured product of the present invention is 30 or more and 70 or less.

[0072] There is no specific limitation on the form of the cured product obtained by curing the composition of the present invention. The form of the cured product can be a coating layer in the form of a thin film, a molded product such as a sheet form, or a filler obtained by injecting and curing at a specific position in the uncured state. Furthermore, the cured product can be used as a sealing material or an intermediate layer applied to a laminate or a display device, etc. The cured product obtained from the composition of the present invention preferably has a coating layer in the form of a thin film, and is preferably a molding material having a thin film form, particularly an insulating molding material having a thin film form.

[0073] The curable composition of the present invention is suitable as an insulating coating agent, a potting agent, or a molding material having a thin film form for electronic and electrical devices, particularly as a stamp material applied to the nanoimprint lithography process.

[0074] [Other additives] Various additives can be added to the composition of the present invention if desired. Examples of additives that can be used include release agents, leveling agents, UV absorbers, antioxidants, fillers (reinforcing fillers, insulating fillers, heat conductive fillers, and other functional fillers), etc. Furthermore, a thixotropy-imparting agent can be added to the composition of the present invention as needed, particularly when used as a potting agent or a sealing agent.

[0075] The composition can be prepared by uniformly mixing components (A) to (C) and other components together as needed. When preparing the composition, it can be mixed at room temperature using various stirrers or kneaders, and can be mixed while applying heat as needed. There are no specific restrictions on the order of addition for each component. They can be mixed together in any order.

[0076] Furthermore, the composition can be a one-component composition, and in consideration of its storage stability, it can be a multi-component composition such as a two-component composition that is mixed before use. Specifically, in the case of a two-component composition, it is preferable that the first component contains a part of component (A) and the catalyst component (C), and the second component contains a part of component (A) and the cross-linking component (B). Furthermore, other optional components can be added to any of the components, but the hydrosilylation reaction inhibitor is preferably added to the second component containing component (B) from the viewpoint of reactivity when all the components are mixed.

[0077] This composition can be cured in a relatively low temperature range including room temperature (for example, in the range of 15 to 80 °C) after irradiation with high-energy rays such as UV rays. Furthermore, the curing reaction of this composition can be controlled to a desired rate by the content of the catalyst metal in component (C), the type and amount of the hydrosilylation reaction inhibitor.

[0078] [Use] The UV-curable organopolysiloxane composition of the present invention can be cured not only by ultraviolet rays but also by electron beams, which is another aspect of the present invention.

[0079] The curable composition of the present invention has a low viscosity and is particularly useful as a forming material for an insulating layer for forming electronic and electrical devices, and as a stamp material applied to a nanoimprint lithography process. The curable composition of the present invention can be applied onto a substrate or sandwiched between two substrates including a material that is transmissive to at least one of ultraviolet rays or electron beams, and can be cured by irradiating ultraviolet rays or electron beams to form an insulating layer. In this case, the composition of the present invention can be patterned when applied to a substrate, and then the composition can be cured. Alternatively, the composition can be applied to a substrate, and cured portions and uncured portions can be left during curing by ultraviolet ray or electron beam irradiation. Thereafter, the uncured portions can be removed with a solvent to form an insulating layer having a desired pattern.

[0080] Since the cured product of the curable composition of the present invention has good transparency, it is suitable as a material for forming an insulating layer for touch panels, displays, and other display devices. In this case, if necessary, any desired pattern can be formed on the insulating layer as described above. Further, since the cured product has high hardness and releasability, it is suitable as a stamp material applied to a nanoimprint lithography process.

[0081] Furthermore, the curable composition can also be used to form an insulating coating layer (insulating film) by curing after coating an article. Therefore, the composition of the present invention can be used as an insulating coating agent. Further, the cured product formed by curing the curable composition of the present invention can be used as an insulating coating layer. Also, the cured body obtained by curing the curable composition of the present invention can be used as an insulating coating layer for electronic and electrical devices, an insulating potting agent, and a stamp material applied to a nanoimprint lithography process.

[0082] The present invention will be further described below based on examples, but the present invention is not limited to the following examples.

Examples

[0083] The UV-curable organopolysiloxane composition of the present invention and its cured product will be described in detail based on examples. Further, the measurements and evaluations in the examples and comparative examples were conducted as follows.

[0084] [Viscosity of Organopolysiloxane and Curable Organopolysiloxane Composition] The viscosity (mPa·s) at 25°C was measured using a rotational viscometer (E-type viscometer VISCONIC EMD, manufactured by TOKIMEC CORPORATION).

[0085] [Preparation of Curable Organopolysiloxane Composition] Each material in the amounts listed in Table 1 below was placed in a brown plastic container and thoroughly mixed using a planetary mixer to prepare a curable organopolysiloxane composition.

[0086] [Preparation of Cured Body from Curable Organopolysiloxane Composition] Approximately 0.65 g of the curable organopolysiloxane composition was poured between two glass substrates having a spacer with a thickness of 1 mm. Through one of the glass substrates, LED light having a wavelength of 365 nm was irradiated onto the composition with an energy exposure of 4000 mJ / cm 2 and then heated in an oven at 80°C for 30 minutes to cure, thereby preparing a plate-shaped organopolysiloxane cured body having a side length of 25 mm and a thickness of 1 mm.

[0087] [Appearance of Cured Body of Curable Organopolysiloxane Composition] The appearance of the plate-shaped organopolysiloxane cured body obtained by the above method was visually evaluated.

[0088] [Hardness of Cured Body of Curable Organopolysiloxane Composition] Four plate-like organopolysiloxane cured bodies obtained by the above method were laminated, and the type D durometer hardness at 25 °C was measured using a digital hardness tester (Asker automatic rubber hardness tester, manufactured by KOUBUNSHI-KEIKI CORPORATION).

[0089] [Toughness of the cured body of the curable organopolysiloxane composition] After the measurement of the hardness, the upper layer of the cured body was visually confirmed, and the toughness of the cured body was evaluated according to the following criteria: "Good": No appearance change was observed, "NG1": Slight cracks were observed from the contact point of the needle edge of the hardness tester, "NG2": Obvious cracks were observed.

[0090] [Examples and Comparative Example 1] A UV-curable organopolysiloxane composition having the composition (parts by mass) shown in Table 1 was prepared using the following components. (A1) Branched organopolysiloxane represented by (Me3SiO 1 / 2 ) 0.38 (Me2ViSiO 1 / 2 ) 0.08 (SiO 4 / 2 ) 0.54 and having a molecular weight of 6,000. (A2a) Branched organopolysiloxane represented by (Me3SiO 1 / 2 ) 0.48 (Me2ViSiO 1 / 2 ) 0.14 (SiO 4 / 2 ) 0.38 and having a molecular weight of 1,200. (A2b) Branched organopolysiloxane represented by (Me2ViSiO 1 / 2 ) 0.8 (SiO 4 / 2 ) 0.2 and having a molecular weight of 432. (A3) Dimethylpolysiloxane having both ends of the molecular chain blocked with dimethylvinylsiloxy groups and a viscosity of 60 mPas (B1) An MQ-type branched organopolysiloxane having a dimethylhydrogen siloxy group and a hydrogen content of 1.0% by mass (B2) A polymethylhydrogen siloxane in which both ends of the molecular chain are blocked with trimethylsiloxy groups and the hydrogen content is 1.4% by mass (C) (Cyclopentadienyl)trimethylplatinum(IV) complex

[0091]

Table 1

[0092] As shown in Table 1, the UV-curable organopolysiloxane compositions (Examples 1 to 6) of the present invention have a viscosity at 25 °C suitable for application to a substrate as a coating agent by spin coating or other coating procedures and have high transparency. The cured products obtained by UV irradiation and subsequent heating are transparent and have a sufficiently high hardness. Therefore, the UV-curable organopolysiloxane compositions of the present invention and their cured bodies are suitable as stamp materials applied to the nanoimprint lithography process. On the other hand, the compositions having too low a viscosity (Comparative Examples 2 and 3) could not provide cured bodies having sufficient toughness. Further, in the composition lacking component (A2) (Comparative Example 4), the hardness of the cured body therefrom was not sufficient. Also, when the alkenyl content of the composition (Comparative Example 1) is outside a specific range, the viscosity is too high and it is not suitable as a coating agent.

[0093] Industrial Applicability The UV-curable organopolysiloxane composition of the present invention is particularly suitable for the uses described above, and in particular, is suitable as a material for forming a stamp material applied to the nanoimprint lithography process.

Claims

1. An ultraviolet (UV) curable organopolysiloxane composition comprising: (A) The following components (A1), (A2), and (A3): (A1) A branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of 2,500 or more, (A2) A branched organopolysiloxane having two or more alkenyl groups in the molecule and a molecular weight of less than 2,500, and (A3) A linear organopolysiloxane having two or more alkenyl groups in the molecule, an alkenyl-functional organopolysiloxane mixture containing the same, and (B) an organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule, wherein the molar ratio of the silicon-bonded hydrogen atoms in component (B) to the alkenyl groups in component (A) is in the range of 0.5 to 4.0, and (C) a photoactivated hydrosilylation catalyst, wherein the mass ratio of components (A1), (A2), and (A3) satisfies the following formula (1): [(A1) + (A2)] / (A3) > 1.3 (1) The content X of alkenyl groups per 100 g of the whole composition satisfies the following formula (2): 110 ≤ X ≤ 220 (2) For the whole composition, the viscosity measured at 25 °C using an E-type viscometer is in the range of more than 80 mPa·s to 500 mPa·s or less, and an organic solvent is substantially not contained in the composition, an ultraviolet (UV) curable organopolysiloxane composition.

2. When the total mass of components (A) to (C) in the composition is 100 parts by mass, the parts by mass of components (A1), (A2), and (A3) are as follows: (A1): 25 to 75 parts by mass, (A2): 3 to 60 parts by mass, and (A3): 5 to 40 parts by mass satisfying the above, the UV curable organopolysiloxane composition according to Claim 1.

3. The UV curable organopolysiloxane composition according to Claim 1, wherein component (A3) is a linear organopolysiloxane having an alkenyl group at its molecular terminal.

4. The UV curable organopolysiloxane composition according to Claim 1, wherein component (B) is a linear organopolysiloxane having two or more silicon-bonded hydrogen atoms in the molecule.

5. Component (A1) has an alkenyl group and the following average unit formula: (R １ ３ SiO １／２ ) ａ１ (R １ ２ SiO ２／２ ) ｂ１ (R １ SiO ３／２ ) ｃ１ (SiO ４／２ ) ｄ１ (3) (In the formula, R １ independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, All R １ Among them, at least two are alkenyl groups having 2 to 12 carbon atoms, and a1, b1, c1, and d1 satisfy the following conditions: a1 + b1 + c1 + d1 = 1, 0 ≦ a1 ≦ 0.5, 0 ≦ b1 ≦ 0.4, 0 ≦ c1 ≦ 0.8, and 0 ≦ d1 ≦ 0.7, 0.5 ≦ c1 + d1 ≦ 0.8), and is a branched organopolysiloxane represented by the formula (1). The UV curable organopolysiloxane composition according to claim 1.

6. Component (A2) has an alkenyl group and the following average unit formula: (R ２ ３ SiO １／２ ) ａ２ (R ２ ２ SiO ２／２ ) ｂ２ (R ２ SiO ３／２ ) ｃ２ (SiO ４／２ ) ｄ２ (4) (wherein, R ２ is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, All R ２ Among them, at least two are alkenyl groups having 2 to 12 carbon atoms, and a2, b2, c2, and d2 are the following conditions: a2 + b2 + c2 + d2 = 1, 0 ≦ a2 ≦ 0.5, 0 ≦ b2 ≦ 0.8, 0 ≦ c2 < 0.5, and 0 ≦ d2 < 0.5, 0 < c2 + d2 < 0.

5. The UV-curable organopolysiloxane composition according to claim 1, which is a branched organopolysiloxane represented by

7. The mass ratio of components (A1), (A2), and (A3) is the following formula (5): [(A1) + (A2)] / (A3) ≥ 1.5 (5) The UV-curable organopolysiloxane composition according to claim 1, which satisfies the above condition.

8. The UV-curable organopolysiloxane composition according to any one of claims 1 to 7, wherein the hardness of the cured body obtained by curing the composition, measured at 25°C using a Type D durometer, is 30 or more.

9. The UV-curable organopolysiloxane composition according to any one of claims 1 to 8, wherein the viscosity of the whole composition, measured at 25°C using an E-type viscometer, is in the range of 100 to 350 mPa·s.

10. The UV-curable organopolysiloxane composition according to any one of claims 1 to 9, wherein component (C) is an unsubstituted or alkyl-substituted (cyclopentadienyl) trialkylplatinum complex.

11. An insulating coating agent comprising the UV-curable organopolysiloxane composition according to any one of claims 1 to 10.

12. A cured body obtained by curing the UV-curable organopolysiloxane composition according to any one of claims 1 to 10.

13. Use of the UV-curable organopolysiloxane composition according to any one of claims 1 to 10 as a stamp-forming material applied to nanoimprint lithography.

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